What is the most efficient method to create a WMS service showing the change between two dates?
I have successfully set up a NDVI WMS service for a single date, and understand the “evaluate pixel” evaluates the pixel for the date. But is there a way to evaluate the pixel for two dates to get the change of the NDVI, and serve that as the layer in the WMS?
If this is not possible, then what would be the best approach to analyze the change between two dates? My thought would be getting the array from both dates and doing the analysis once data is received from the service, but before I do so I thought I’d pose the question first.
Due to some inexperience in Sentinel Hub Python API usage, I thought it may be best to ask on this forum Thank you in advance.
Yes, it is possible to get the change of the NDVI of two dates. In the evalscript, there’s a parameter mosaicking which allows you to define how the source data is mosaicked. When specifying ORBIT or TILE, you can get NDVI time series in an array and analyse the difference.
You may want to take a look at the mosaicking section of our documentation. In this post you can find some concrete examples about how to access time series in your evalscript.
I also recommend our Multi-Temporal Scripts and Data Fusion workshop. In part 2 the mosaicking is explained and in part 3 there are examples of multi-temporal script which may give you ideas to implement NDVI difference analysis.
Thank you in advance.